They travel across an internet packet or a single network frame.. Messages in single networks are called frames, not packets.. Point-to-Point Single Networks, Physical Links, and Data li
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o utions anua or usiness ata et or s and ecurity 10th Edition y
ay ond Pan o, Julia L Panko
Link full download: https://getbooksolutions.com/download/business-data-networks-and-security-10th-edition-by-panko-solutions-manual/
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WELCOME TO THE CLOUD
NETFLIX DIVES INTO THE AMAZON
Test Your Understanding
1 a) Why is the Internet usually depicted as a cloud?
It symbolizes that users should not have to know how it works, just as you do not have to
know how the electrical system works when you turn on a light
b) What is the significance of this depiction for users?
The operation of the Internet should be hidden from them
Hosts, Messages, and Addresses
Test Your Understanding
2 a) What is the term we use in networking for any computer attached to a network?
Host
b) Is your smartphone a host when you use it to surf the ‘Web?
Yes By definition
c) Are you as a person a host when you use a network?
No You are not a computer! Always go back to the definition
d) How do application programs on different hosts communicate?
They send messages to each other
3 a) What kind of addresses do hosts have on the Internet?
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Internet Protocol (IP addresses)
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b) What kind of address is 128.171.17.13?
IPv4
c) What name do we use for the format 128.171.17.13?
Dotted decimal notation
d) Who uses this format—humans or computers?
Humans
e) Convert the following 32-bit binary IP address into DDN (spaces are added for easier reading):
10000000 10101011 00010001 00001101 (Check Figure: 10000000 = 128 In the first printing, this was erroneously printed as 127.)
128.171.17.13
f) Convert 5.6.7.138 into a 32-bit IP address (Check Figure: 5 = 00000101) Show a space between each 8-bit segment
00000101 00000110 00000111 00001100
g) What type of IP addresses is 32 bits long?
IPv4
h) What other type of IP address exists, and how long is its addresses?
IPv6, 128 bits
The Internet
Test Your Understanding
4 a) Is the Internet a single network? Explain
The Internet is not a single network It is a collection of single networks and smaller internets
b) What is the role of ISPs?
ISPs collectively form the core of the Internet, which is also called the Internet’s backbone
c) Who controls the Internet?
No one
d) Who funds the Internet?
Users—both individual and corporate
Netflix Dives into the Amazon
Test Your Understanding
5 a) List Netflix’s content delivery requirements
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Users will not tolerate delay or unreliability
b) What is transcoding?
Changing a movie or other video into a form that can be delivered to consumers by Netflix or another streaming services
c) Why does Netflix make many transcoded versions of each movie?
To serve the particular needs of specific user equipment and network conditions
d) How does Netflix use AWS?
For transcoding, selecting the best transcoded version for a particular user and set of network conditions, and personalized recommendations
e) How do content delivery networks reduce streaming delays to customers?
They place a local content server near the user Either near the user’s ISP or within the user’s ISP’s premises
Virtualization and Agility
6 a) Distinguish between physical servers and virtual machines
Physical servers are real computers Virtual machines are parts of a server that act like computers but are not A physical server may have many virtual machines VMs can be quickly spun up, spun down, or moved to different physical servers
b) What can be done with virtual machines that would be difficult to do with physical servers?
Nearly instantaneous setup, tear-down, and movement to another machine
c) What is VM instantiation?
Creating a new VM
d) How does Netflix use the agility offered by Amazon Web Services?
It spins up additional VMs during peak viewing time and tears them down in low viewing periods
Infrastructure as a Service (IaaS) and Software as a Service (SaaS)
7 a) What is a CSP? (Do not just spell out the acronym)
A cloud service provider that provides a service opaquely so that customers do not have to worry about the details
b) Distinguish between IaaS CSPs and SaaS CSPs
IaaSs provide VMs with operating systems but no application software
SaaSs provide VMs complete with specific application software
c) Is AWS an IaaS or a SaaS for Netflix?
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AWS is an IaaS provider
d) Is Google an IaaS or a SaaS for Netflix?
Google is a SaaS provider
e) Who owns and manages the servers in IaaSs and SaaSs?
The cloud service provider in both
f) Who owns and manages the applications in IaaSs and SaaSs?
The cloud server provider in SaaS; the customer in IaaS
g) In AWS, what does Netflix manage and not manage?
It does not manage the servers except in the sense of creating, deleting, or moving them
It does manage the applications
Clients Move into the Cloud
8 a) When a cloud virtual client is used, describe what happens when a user moves from one physical client device to another
All data files, applications, and application program personalizations are available to them
b) How does the use of virtual clients facilitate file sharing among customers of the system?
Virtual clients can share files with other virtual clients easily
c) What are the advantages of using cloud application programs as a service, compared to
traditional application purchasing?
It avoids large one-time expenses in buying software and replaces it with smaller monthly expenses to pay for the service
At least some of the management work is outsourced to the CSP
Rain Clouds: Security
9 What concerns do customers have about cloud security?
That critical corporate data in the cloud may be hacked, that the government may be secretly looking at their data
Networks and the Cloud
10 Describe the relationship between cloud computing and networking
The explosive growth of cloud computing is putting a strain on network capacity
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Service Level Agreements (SLAs): Speed
11 a) What are service level agreements?
Service level agreements (SLAs) are guarantees that the CSP will meet specified service parameters or pay a penalty
b) What happens if a service provider fails to meet its SLA?
It must pay a penalty
c) Is network speed usually measured in bytes per second (Bps) or bits per second (bps)?
bits per second (bps)
d) How many bits per second is 56 kbps without a metric prefix (In other words, how many bits per second is it?)
56,000 bps
e) Express 47,303,000 bps with a metric prefix
47.303 Mbps
f) Why do you need to know what application you are using to know what connection speed you need?
Some applications, such as e-mail, do not need fast connection speeds to be effective Others, such as video streaming and data backup, do
g) Distinguish between speed to individuals and corporate network speeds
Speed to individuals is what individual employees experience Corporate network speeds must
be high enough for the aggregate speeds of individual employees
12 a) How would you write four thousand bits per second in metric notation?
4 kbps
b) How would you write 45,250,000 bps in metric notation?
45.25 Mbps
c) How would you write 23.78 Mbps without a metric prefix?
23,780,000 bps
d) How would you write 0.047 Mbps without a metric prefix?
47,000 bps
13 a) Write 45.6355 kbps properly
WRITING SPEEDS IN METRIC NOTATION
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It is written properly
b) Write 37,400 Mbps properly
37.4 Gbps
c) Write 0.032 Mbps properly
32 kbps
d) Write 37kbps properly
37 kbps (needed a space)
e) Write 89k bps properly
89 kbps (needed a space and bps)
MESSAGES
Application Messages
Message Fragmentation, Frames, and Packets
14 a) What is fragmentation?
Dividing an (application) message into many smaller parts that will each be sent in a packet
or frame
b) What are frames or packets?
They are small messages that carry application message segments They travel across an internet (packet) or a single network (frame)
c) How does fragmentation improve error handling?
If there is a transmission error, only a single frame or packet is resent—not the entire applications message, which can be very long
d) What is multiplexing?
Having the packets or frames of multiple users share a physical transmission line
e) How does fragmentation reduce transmission cost through multiplexing?
Individual users do not have to pay for an entire line; they only pay for the capacity they actually use
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SINGLE NETWORKS
Test Your Understanding
15 What are the three defining characteristics of single networks?
A single networks uses a single technology for transmission All devices must comply with that technology’s standards
There is a controlled address space such that each host address is unique, like a telephone number
Messages in single networks are called frames, not packets
Single-Network Host Addresses
16 a) What is the most widely used single-network address?
EUI-48
b) What else is it called?
MAC address
c) Why is the following NOT an EUI-48 address: A9-00-FF-93-BD?
There are only five symbol pairs, not six
d) Are all single-network addresses EUI-48 addresses?
No
Point-to-Point Single Networks, Physical Links, and Data links
17 a) In what type of single-network technology is the Point-to-Point (PPP) protocol used?
Point-to-point
b) What do physical layer standards govern?
Connectors and physical transmission
c) What do data link layer (DLL) standards govern?
Frames and switch operation
d) At what layer do you find EUI-addresses? (The answer is not directly in the text It requires you
to integrate the information you have learned.)
Data link layer
e) At what layer are frames defined?
Data link layer
18 a) Why is layering important for creating standards?
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It breaks the standardization job into smaller pieces that can be worked on by specialists in that area
b) What is the name and number of the lowest network standards layer?
Physical layer, Layer 1
c) What is the name and number of the second-lowest network standards layer?
Data link layer, Layer 2
d) At which layers are standards defined for single-network technologies?
Layers 1 and 2
e) At what layer or layers is PPP a standard?
Layer 2 because it defines frame organization
Wireless Single Networks
19 a) In 802.11 Wi-Fi networks, what device relays frames between the source and destination hosts?
Wireless access point
b) What two things do 802.11 data link layer standards govern?
Frame organization and access point operation
c) Is there always a single data link for a frame in a single network?
Yes
Switched Single Networks
20 a) What decision do switches have to make when a frame arrives?
Where to send it next
b) What is this decision called?
The switching decision
c) How do they make this decision?
Their switching table specifies where to send the frame next, based on the frame’s
destination address
d) Does an individual switch know the frame’s entire path through a switched single network?
No Only the next hop
e) Are frames addressed to the DLL addresses of a switch or the DLL addresses of a destination host? (The answer is not in the text.)
Destination hosts Switches merely read the DLL address in the frame in order to pass it on to the destination host with the destination DLL address
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Hybrid Switched/Wireless Single Networks
21 a) Can you have a mixed wired and wireless network?
Yes
b) In a hybrid single-switched network, why do wireless clients need to connect to the wired network?
This is where resources are that then need, including servers and the firm’s Internet access router
c) What role do access points have in hybrid switched/wireless networks?
They translate between wireless client frames and wired network frames
INTERNET TRANSMISSION
Hosts on Different Single Networks
22 If two hosts are on two different single networks, what three problems must be overcome if they are to be able to communicate?
First, the single networks may have different standards They would not be able to make sense of each other’s frames
Second, even if the two networks follow the same standard, this does not mean that they can interoperate Most fundamentally, a host on one network may have the same DLL address as
a host on the other network
Third, how would you link the two networks together? If the link used the standards of one network, it would not connect to the other network for the first two reasons
Creating the Internet
23 a) What device connects different single networks together into an internet?
A router
b) Do single networks know that they are delivering frames to a router?
No
c) To what type of device do single networks think they are delivering frames?
A destination host
d) What devices understand what is really happening?
The router and the source and destination host
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24 Why was a new type of address needed for the Internet?
There needed to be an address that would be unique worldwide, unlike data link layer
addresses
25 a) On the Internet, what new type of message travels between the source and destination host?
The Internet Protocol (IP) packet
b) How are these messages carried in single networks?
Inside frames
c) Describe what happens to a packet between the source and destination host
The source host places the packet in a frame for the network to the first router
Each router along the route receives a frame, removes the packet, and places it into a frame for the next-hop-router
The final router delivers the frame to the destination host The destination host removes the packet from the frame
d) Draw a frame in terms of encapsulation, assuming that the frame comes from a contemporary host
There will be a frame header, followed by the packet, perhaps followed by a frame trailer
Routes and Layer 3
26 a) What is a route?
The path that a packet takes across an internet from the source host to the destination host
b) Distinguish between a data link and a route
A data link is a path a frame takes through a single network
A route is the path a packet takes through an internet from the source host to the destination host
c) When a packet travels through an internet, are there usually more data links or routes along the way?
Data links
d) How many routes are there when a packet is transmitted?
One
e) When a packet is transmitted from a source host to a destination host separated by four single networks, how many packets will there be? (Answer: 1)
1
f) How many frames will there be? (Answer: 4)
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4
g) When a packet is transmitted from a source host to a destination host separated by 17 single networks, how many packets will there be?
1
h) How many frames will there be?
17
27 a) Distinguish between physical links, data links, and routes
Physical links are connections between adjacent devices on the transmission path
A data link is a path a frame takes through a single network
A route is the path a packet takes through an internet from the source host to the destination host
b) When Host A in Figure 1-26 transmits a packet to Host D, how many physical links, data links, and routes will there be?
7
c) How many packets will there be?
3
d) How many frames? (Answers: 7 physical links, 3 data links, 1 route, 1 packet, 3 frames.)
1
28 a) When Host A in Figure 1-26 transmits a packet to Host C, how many physical links, data links, and routes will there be?
3-4 physical links, depending on the data link
1 data link
1 route
b) How many nodes will there be along the route?
2 or 3 depending on the data link
c) How many packets will there be?
1
d) How many frames?
1
29 a) At what layer do you find: a) IP addresses,
Layer 3 (internet)
b) EUI-48 addresses,